What possessive pronouns do have an apostrophe?

I taught English for twenty-eight years, and I think that the confusion is that none of the possessive pronouns use apostrophes. This is confusing because possessive nouns use apostrophes. The pronouns mentioned, such as everyone's, etc., are indefinite pronouns--not possessives.

The condensation of prose by dropping apostrophes and hyphens works at both local and global scales. "Stopsign" began as "stop sign" thence 'stop-sign". "Right of way" remains standard for the property right incident real estate), except "right-of-way" when used to denote a patch of ground. Similarly, the myth than Twain said or wrote "History doesn't repeat itself, but it rhymes." stems from a passage in the preface to "The Gilded Age: A Story of To-Day" (2nd Ed). Such changes amble along with the lingo, and the less we see of words sporting the dispensible the less we care for them in general.

Yet the rate of typographic attrition also has an idiosyncratic component. The apostrophe in "van der Waals' force" was hastily dropped because it was being used so much and so often. (The gloss of the Nobel committee is somewhat vague: in paraphrase, "for making vast domains of science possible".) The notation for molecular structure in chemical physics where the force matters a lot involves apostrophes, which leads to a sometimes amusing mishmash of grams and grammar. (The hyphen in "mish-mash" survives in Bulgarian cuisine. Dr. Johnson called it "a low word", and that's the perhaps low-down lowdown.)