Question about future optative

[Bart]

I'm reading Lysias I (On the Murder of Erathostenes) in the edition by Geoffrey Steadman and encountered the following difficulty

Lys 1.23
εἰδὼς δ᾽ ἐγὼ ὅτι τηνικαῦτα ἀφιγμένος οὐδένα καταλήψοιτο οἴκοι τῶν ἐπιτηδείων, ἐκέλευον, συνδειπνεῖν

(As I knew that, arriving at that hour, he would find none of his circle at home, I invited him to dine with me)

Steadman says in his notes that καταλήψοιτο is an aorist optative, but surely that has to be future optative instead. But why use a future optative here? I remember Mastronarde mentioning somewhere that the future optative has a very restricted use, but I don't think he expands on this. Any thoughts?

[Qimmik]

Here it's used in indirect discourse where the main verb is in the past to substitute for what would be a future indicative in direct discourse. I think that's the main use for the future optative--in indirect discourse where the "sequence of moods" requires an optative and the verb would be in the future indicative in direct discourse.

[Bart]

Thanks!

[Qimmik]

Lysias is a good way to learn to read Greek prose. (Actually, the attribution to Lysias of most of virtually all the speeches collected under his name, with the exception of No. 12, can't be verified, and there's considerable doubt.) The speeches are written in clear but not unsophisticated Attic Greek. They served as a model for Greeks learning to write good Greek for two millenia (and that accounts for their survival to the present). Also, with a good commentary (and a number of them are available at reasonable cost), you can absorb a lot of information about Athenian daily life, legal procedure, social norms, etc. around 400 BCE, and they give insight into the thinking of the Athenian man in the street. After Lysias, you can move on to Demosthenes and Thucydides. Lysias 1 is a particularly appealing speech because it involves sex and murder.

Some other uses of the future optative are mentioned in Smyth, but they are all instances of subordinate clauses in past time where a future indicative would be used in an independent clause.