Train station in Strasbourg - does it have lockers for bag storage?

Yes, there are lockers.

According to this, yes:

https://strasbourg.city-locker.com/en/luggage-storage-strasbourg/1-strasbourg-train-station-luggage-locker.html

Yes there are lockers, but you may not be able to use them.

Last September we arrived (by air) to Strasbourg. Our plan was to take the shuttle from the airport to the city center, and drop our bags at the train station - because, the guide book said there were lockers. We planned to wander the city for a few hours, visiting the cathedral and taking in the vibe. Later that day, we would go back to the train station, retrieve out bags, and take the train to Colmar, where we would stay 3 nights.

However, upon finding the luggage office at the train station, we were informed that the lockers were all full and none were available. We were then told that we could leave our large bags with them, and they would watch them (no lockers) for a fee. The fee turned out to be €10 per bag, if I recall correctly. This felt like a scam at the time (and I'm pretty sure it was), but still, what you gonna do? We had (I think) 3 large and heavy bags and of course didn't want to slog around the city dragging them. So I paid up and wrote it off. YMMV.

I'm not sure I consider 10 euro a bag a scam. We checked bags in Sicily at a hotel for a day for 10 Euro. We checked bags at Pompeii Scavi and I'm sure it was 5 euro a bag if not more.