Exegesis:

eulogēmenos ho erchomenos ho basileus en onomati kuriou ‘blessed (is) the coming one, the King, in the name of the Lord,’ cf. on 1.42. Since ho erchomenos is virtually a title (cf. on 7.19), ho basileus is in apposition to it. en onomati kuriou goes with ho erchomenos.

en ouranō eirēnē kai doxa en hupsistois ‘in heaven (is) peace, and glory in the highest,’ chiastic clause. For eirēnē cf. on 1.79. Here it refers to the eschatological peace after the expulsion of Satan from heaven (cf. 10.18). For doxa en hupsistois cf. on 2.14.

Translation:

Blessed is the King who comes in the name of the Lord, preferably, ‘blessed is he who comes, the King, in the name of the Lord.’ Cf. also on 13.35.

Peace in heaven. For peace see on 1.79; the positive aspect of the term is dominant here.

Glory in the highest, i.e. glory/honour/praise is in the highest (heaven). A personal referent may be preferable or obligatory here, e.g. ‘to God in the highest (heaven),’ ‘to the Most High,’ or simply, “to God” (Good News Translation); and one may have to shift to a verbal construction, e.g. ‘praised/exalted/honoured is’ (cf. Tzeltal), or, ‘we praise/exalt/honour.’ For glory and in the highest see on 2.14.

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.