Exegesis:

idou ‘behold,’ cf. on v. 32.

aphietai humin ho oikos humōn ‘your house is abandoned to you,’ i.e. is left to your own care without protection from God. oikos may refer to the city of Jerusalem or to the temple, preferably the former.

legō [de] humin ‘I tell you,’ cf. on 3.8.

ou mē idēte me heōs [hēxei hote] eipēte ‘you will not see me till (the time) will come when you say,’ as if Jesus had already left Jerusalem for the last time in his earthly life. hēxei is impersonal.

eulogēmenos ho erchomenos en onomati kuriou ‘blessed is he who comes in the name of the Lord,’ a Messianic exclamation and greeting, here referring to the (eschatological) moment when Israel will acknowledge Jesus as its Messiah. en onomati kuriou means ‘as one who is sent and authorized by the Lord,’ i.e. by God.

Translation:

Your house is forsaken, or, ‘God will leave your house to you’ (Sranan Tongo), ‘God no longer concerns himself about your house.’ House, literally translated, often has too restricted a meaning here; hence, “home” (Good News Translation), ‘habitation’ (Bible de Jérusalem), ‘place where you (plur.) live.’

For blessed see on 1.42, sub (1).

He who comes in the name of, or ‘supported by (lit. having-as-bridge) the name of’ (Toraja-Sa’dan), ‘with/carrying the name of.’ Where such a rather literal rendering would be incomprehensible one will have to describe the meaning of the phrase, e.g. ‘the one sent by’ (cf. Tzeltal, Shona 1966), ‘the one who comes as the Lord’s namesake (cf. Guhu-Samane), or, as the representative of the Lord, or, to represent the Lord.’

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.