A.like ὅτε, exc. that the sense is less definite (cf. X.Cyr.1.6.3), though the two were freq. used without distinction :
I. Relat., with the ind., mostly with reference to the past, when, Il.1.399,3.173, etc. ; the ind. ἦστε is omitted, 8.230 : in Class. Att. Prose only ὅτε is so used, when referring to a particular time, but later ὁπότε returns, as ὁπότε περιῆν when she was alive, POxy.243.10(i A. D.): with the pres. in a simile, “ὡς δ᾽ ὁπότε . . ποταμὸς πεδίονδε κάτεισι” Il.11.492 : with subj., like ὁπόταν, with reference to an indef. number of occasions in the pres. or to the future, “ὁππότ᾽ Ἀχαιοὶ Τρώων ἐκπέρσωσ᾽ εὖ ναιόμενον πτολίεθρον” 1.163, cf.13.817, 21.112, Od.14.170, Hes.Th.782 : sts. in similes, “ὡς ὁπότε νέφεα Ζέφυρος στυφελίξῃ” Il.11.305, cf. Od.4.335 ; but ὁπότ᾽ ἄν, Ep. ὁπότε or ὁππότε κεν, is more common with subj., and in Att. Prose ἄν must be used, v. ὁπόταν: Cyrenaic ὁπόκα κα δήληται Berl.Sitzb. l. c.
2. with opt. :
a. to express an event that occurred often, “ὁπότε Κρήτηθεν ἵκοιτο” Il.3.233, cf. 10.189, 15.284, Od.11.591, Th.1.99,2.15, Pl.Smp.220a, X.An.3.4.28.
b. after a verb of waiting, of a time future relatively to the past, “ἷζε . . δέγμενος ὁππότε ναῦφιν ἀφορμηθεῖεν” Il.2.794, cf. 4.334,7.415,9.191,18.524.
c. in orat. obliq., S.Tr.824 (lyr.), X.An.4.6.20 ; in implied orat. obliq., Od.24.344 (of a past promise) ; ἀποδοτέον . . ὁ. μανεὶς ἀπαιτοῖ we were not [as you remember] to . . , Pl.R.332a.
d. where the principal clause has an opt., “μηδ᾽ ἀντιάσειας ἐκείνῳ ὁππότε νοστήσειε” Od.18.148, cf. Pl.R.396c, X.Cyr.1.6.3.
II. in indirect questions, with ind., ἦ ῥά τι ἴδμεν . . ὁππότε Τηλέμαχος νεῖται; when he is to return, Od. 4.633 ; “εἰς ὁ.” by what time, Aeschin.3.99 : rarely after a past tense, προσεδέρκετο, δέγμενος αἰεί, ὁππότε δὴ . . ἐφήσει (for ἐφείη, v. supr. 1.2 b) Od.20.386 ; “εἰς σὲ βλέψαι καὶ τὸν ταμίαν ὁπότ᾽ ἄριστον παραθήσει” Ar.V.613.
III. “ὁποτεοῦν” at any time whatever, Arist.Metaph. 1049a1.
B. in causal sense, because, since, with ind., Thgn.749 (s. v.l.), Hdt.2.125, Pl.Lg.895c, etc. ; also “ὁπότε γε” S.OC1699 (lyr.), X.Cyr. 8.3.7.