Activate Orange Holiday card before landing?

You do find out your French phone number as soon as you buy the eSIM, but if you need to receive a verification text to set up the IDF Mobilities account, you won't be able to do that. The eSIM won't have any reception on American soil.

Also a lesson with Orange that I found out the hard way - the time starts ticking on your eSIM the moment you buy it, even if you don't start using it for a few days. Make sure you don't cut yourself short, or you'll be like me, suddenly without data or reception with several days left in your trip. For an hour, I thought my phone was broken, until it dawned on me. I bought another eSIM and of course it worked fine the rest of the trip, but it was frustrating to spend 20 more euros needlessly.

My Orange esim purchased for France assigned me a phone number with a Polish country code. It would not work for setting up an IDF Mobilities account.

Just turn on your phone when wheels touch down. It takes a minute or two to connect to the data, but you’ll have plenty of time during taxiing, and such.

I bought a regular simcard from Orange, before my recent trip, not esim.
I put it in my phone while flying and as soon as I landed in Zurich it was working.
I didn’t have to do anything to activate it and it was seamless from my entire trip in France….I just changed planes in Zurich.

My Orange esim purchased for France assigned me a phone number with a Polish country code.

That is seriously screwy. I'd complain to a local B&M Orange dealer about that.