4 days itinerary in Switzerland

Probably not the best time to visit the high alps. Too late to ski and too early to hike. But if that is your window of opportunity, so be it. Matterhorn is a long way from Luzern. Hate to go all that way for a day trip and have it socked in. They film those spectacular videos on perfect days of course. So stay flexible with your plans and keep an eye on the weather. Who knows, it could be perfect.

If you think you will have more than 240 chf of train tickets for each adult, the Swiss 30-day Half Fare Card will save money. You can get a free Family Card and your daughter travels with you free. The card is 120 chf per adult. Swiss Passes are outrageously expensive IMO, and they still only give 50% off mountain excursion trains, and in the case of the Jungfraujoch, only 25%.

I assume you will be arriving on the TGV in Zurich, then change to the train to Luzern. So get the Half Fare Cards at Zurich station when you arrive, then everything will be half price.

Zurich is expensive (what in Switzerland isn't) and it is easy to get to the airport or main station quickly from Luzern, so you might give it a pass unless there is something special you have in mind.

Amit, Sam,
If you are travelling from Paris to Luzern (or to anywhere in the Berner Oberland), DO NOT change trains at Zürich. Get off the TGV at Basel, and change there for a train to Luzern (or to Interlaken, Lauterbrunnen or wherever).
Basel is 1 hour before you reach Zürich. Continuing on to Zürich involves doubling back and wasted time (and money).
See Swiss Rail network map here: https://www.sbb.ch/content/dam/sbb/de/pdf/freizeit-ferien/ferien-kurztrips-schweiz/internationale-gaeste/sts-geltungsbereich.pdf

With 4 days (3 nights) you need to choose one place as a base. Either Luzern or the Berner Oberland. Do not waste time on Zürich. Zermatt and the Matterhorn is also too far away. If you choose Luzern, Titlis is convenient, Jungfraujoch is not. If you choose the Berner Oberland it is vice-versa. Whichever you choose, do a day trip on the Brünig Bahn (Interlaken-Luzern) to see both places and the very scenic route in between.

Where will you be going after you leave (airport, train?). That also could affect your decision.

Thanks Sam, Thanks Chris.

1) So as I understand, Zermatt/Matterhorn not advisable, which is fine as per logic given.
2) Suggesting to get down at Basel, which is also noted.
3) On Rail Half card, not sure how to derive at that we will spend CHF250 or more per adult. I had mentioned the itinerary and reiterating again, suggest if it will -
18th April Evening - Reaching Lucerne
19th April - Mt. Titlis
20th April - Jungfraujoch
21st April - Zurich
I also would want to include "Interlaken" somewhere above. My flight on 22nd Morning (11:25), keeping that in mind, kindly suggest -
a) Rail Half card or Swiss Pass,
b) Any change in itinerary for better,
c) If Zurich is not advisable, is it possible to reach Airport on time from Lucerne (or wherever you suggest) same morning?
d) If yes, how to utilize 21st in best possible manner,

Thanks in advance.

Amit,
To work out how much your travel will cost, whether a ½ fare card is worth it, and to get times, use the Swiss railways website: www.sbb.ch

Visiting Jungfraujoch from Luzern in one day is a long day, it takes over 4 hours. I just looked it up on www.sbb.ch If you leave Luzern at 07:05:

Luzern depart 07:05, Interlaken Ost arrive 08:55
Interlaken Ost depart 09:05, Lauterbrunnen arrive 09:25
Lauterbrunnen depart 09:37, Kleine Scheidegg arrive 10:20
Kleine Scheidegg depart 10:30, Jungfraujoch arrive 11:22

As you can see it goes through Interlaken, but you won't have an spare time to stop off on that day. But the route from Luzern to Interlaken (Brünig pass railway) is very scenic.
You could use your extra day (21st) for a boat trip on the lake (see here for details). Or just look around Luzern.
Luzern to Zürich airport is easy. For an 11:25 departure, I assume you need to get to the airport 2 hours before. I found the following trains on www.sbb.ch

Luzern depart 06:35, Zürich Flughafen arrive 07:42
Luzern depart 07:10, Zürich Flughafen arrive 08:13
Luzern depart 07:35, Zürich Flughafen arrive 08:42
Luzern depart 08:10, Zürich Flughafen arrive 09:13

Plenty to choose from!

Thank again Chris. Then should I follow below -

18th April - Paris to Interlaken
19th April - Interlaken to Jungfraujoch and return
20th April - Interlaken to Lucerne in the morning then at the LUCERNE trip at leisure
21st April - Lucerne to Mt. Titlis and return
22nd April Morning - Check Out from Lucerne to Zurich airport.

Is above making sense or anything I am missing? Thanks in anticipation.