97(6) After prepositions, the emphatic forms of the personal pronouns are ordinarily used.
Examples (audio):
ἐξ ἐμοῦ, not ἐκ μου
ἀπ' ἐμοῦ*, not ἀπό μου
δι' ἐμοῦ, not διά μου
ἐν ἐμοί, not ἔν μοι.
But πρός με is common.
*The final vowel of prepositions is frequently elided before words that begin with a vowel. The elision is marked by an apostrophe.