I thought (as someone who only recently spelt "printemps" wrong ) that the French pronunciation for "en-" was more like on- than ahn-. Is this a transpondial thing?

We never pronounce the "-lope" on the end in the French style, which makes me wonder if word endings get assimilated first.

Anyway, it'd always be an EN-veh-lope to me. To my mind, as words of French origin become fully absorbed into English it comes across as increasingly pretentious resuscitating French sounding bits (poshification again). My practice is mirrored on the other side of the Channel - the French pronounce "football" as a French word, for instance.

This reminds me of garage = gar-idj or gar-ahhj. Though that's another can of worms, so forget I said it.