Sense

1. (of time) when, (with indicative, to denote single events) when
2. (with present, of a thing now happening)
3. (rarely with future)

Examples

• Αὕτη ἡ βίβλοσ γενέσεωσ οὐρανοῦ καὶ γῆσ, ὅτε ἐγένετο. ᾗ ἡμέρᾳ ἐποίησε Κύριοσ ὁ Θεὸσ τὸν οὐρανὸν καὶ τὴν γῆν (Septuagint, Liber Genesis 2:4)
• ὅτε ἐργᾷ τὴν γῆν, καὶ οὐ προσθήσει τὴν ἰσχὺν αὐτῆσ δοῦναί σοι. στένων καὶ τρέμων ἔσῃ ἐπὶ τῆσ γῆσ. (Septuagint, Liber Genesis 4:12)
• Καὶ αὗται αἱ γενέσεισ Σήμ. καί ἦν Σὴμ υἱὸσ ἑκατὸν ἐτῶν, ὅτε ἐγέννησε τὸν Ἀρφαξάδ, δευτέρου ἔτουσ μετὰ τὸν κατακλυσμόν. (Septuagint, Liber Genesis 11:10)
• καὶ ἐπορεύθη Ἅβραμ, καθάπερ ἐλάλησεν αὐτῷ Κύριοσ, καὶ ᾤχετο μετ̓ αὐτοῦ Λώτ. Ἅβραμ δὲ ἦν ἐτῶν ἑβδομηκονταπέντε, ὅτε ἐξῆλθε ἐκ Χαρράν. (Septuagint, Liber Genesis 12:4)
• καὶ ἐγένετο ἡνίκα εἶδε τὰ ἐνώτια καὶ τὰ ψέλλια ἐν ταῖσ χερσὶ τῆσ ἀδελφῆσ αὐτοῦ καὶ ὅτε ἤκουσε τὰ ρήματα Ρεβέκκασ τῆσ ἀδελφῆσ αὐτοῦ λεγούσησ. οὕτω λελάληκέ μοι ὁ ἄνθρωποσ, καὶ ἦλθε πρὸσ τὸν ἄνθρωπον ἑστηκότοσ αὐτοῦ ἐπὶ τῶν καμήλων ἐπὶ τῆσ πηγῆς (Septuagint, Liber Genesis 24:30)

Source: Ancient Greek entries from Wiktionary