There's an institution called L'Institut des Hautes Études Scientifiques whose abbreviation is IHÉS. When I pronounce it, should I say it as
i - h - é - s
or is it OK to read it out as
i - h - e - s ?
Generally, if an abbreviation contains É or È, how should I pronounce it? (I'm asking this because I sometimes encounter non-French people who use the latter pronunciation...)