Ancient Greek apostrophe marking elision

[Richard Wordingham via Unicode]

On Fri, 25 Jan 2019 17:02:25 -0500
James Tauber via Unicode <unicode at unicode.org> wrote:

> I guess U+02BC is category Lm not Mn, but doesn't that still mean it
> modifies the previous character (i.e. is really part of the same
> grapheme cluster) and so isn't appropriate as either a vowel or an
> indication of an omitted vowel?

To quote TUS:

"A few may modify the following letter, and some may serve as a
independent letters".

Bear in mind that one of the uses of U+02BC is the scholarly
representation of a glottal stop, especially in Arabic names.

Richard.