Look up the Greek Grammar by Smyth, pp 23-24, paragraphs 70-75 where there is a lot of discussion. To quote Smyth,
"Elision is the expulsion of a short vowel at the end of a word beginning with a vowel. An apostrophe marks the place where the vowel is elided."
I think you must be careful when using elision in the systematic and inexorable way you describe.