Duzenn

e (non ex) ante litteram consonantem (ex aere sed e Republica); it's the same sound problem as in English, actually you say a box but aN apple --Helveticus montanus (disputatio) 10:18, 7 Augusti 2012 (UTC)

Apud Cassell's: "ex before vowels always; e often [sed non semper!] before consonants." IacobusAmor (disputatio) 10:49, 7 Augusti 2012 (UTC)

Apud White's: "ēx or ē (the latter form only before consonants, and even there far less frequently [N.B.] than ex)." IacobusAmor (disputatio) 10:52, 7 Augusti 2012 (UTC)