Chaise longue is French. It means 'long seat'. Its plural is chaises longues.
So many Americans spell it as 'chaise lounge' that I consider it to be a language change and no longer bother to correct it. The problem is, what is/are the acceptable plurals of the American term. I've seen 'chaises lounge', 'chaises lounges' and 'chaise lounges', the latter in a dead tree novel which has sold over 110 million copies worldwide (and IMO is badly edited - I've spotted several obvious mistakes, including a character name change and 'showed' instead of 'showered')
So, for editors and proofreaders, what do you accept as the plural form?