En as in awning

That'd definitely not right in terms of how Brits say "awning" (aw sound like "lawn", "prawn", "born" almost).

The en- sound in envelope in French, spoken by the French, is the same as the -en- sound in lent ("slow"). Or as in entre ("between"), come to think of it. Same applies to most "-en-" words in French that spring to mind. The sound is much much more like "on" than "ahn" or "awn".

I suspect there are Transpondial vowel sound differences making their presence felt here.

Or maybe I'm just plain wrong, and my memory/awareness of French is failing me.