From the
General Instruction on the Liturgy of the Hours.
41. Morning prayer and evening prayer begin with the introductory verse, God come to my assistance. Lord, make haste to help me. There follows the Glory to the Father, with As it was in the beginning and Alleluia (omitted in Lent). This introduction is omitted at morning prayer when the invitatory immediately precedes it.
60. If the office of readings is said before morning prayer, the invitatory precedes it, as noted (nos. 34-36). Otherwise it begins with the verse, God, come to my assistance with the Glory to the Father, As it was in the beginning, and the Alleluia (omitted in Lent).
79. The daytime hours begin with the introductory verse, God come to my assistance with the Glory to the Father, As it was in the beginning, and the Alleluia (omitted in Lent). Then a hymn appropriate to the hour is sung. The psalmody is next, then the reading, followed by the verse. The hour concludes with the prayer and, at least in recitation in common, with the acclamation, Let us praise the Lord. R. And give him thanks.
85. Night prayer begins like the other hours, with the verse, God, come to my assistance, the Glory to the Father, As it was in the beginning, and the Alleluia (omitted in Lent).
120. During the Easter season Alleluia is added to all antiphons, unless it would clash with the meaning of a particular antiphon.
137. At evening prayer, after the two psalms, a canticle of the New Testament is inserted, from the letters of the apostles or the Book of Revelation. Seven canticles are given for each week of the four-week cycle, one for each day. On the Sundays of Lent, however, in place of the Alleluia Canticle from the Book of Revelation, the canticle is from the First Letter of Peter. In addition, on the solemnity of the Epiphany and the feast of the Transfiguration the canticle is from the First Letter to Timothy; this is indicated in those offices.
214. The liturgy of the hours takes on a paschal character from the acclamation, Alleluia that concludes most antiphons (see no. 120), from the hymns, antiphons, and special intercessions, and from the proper readings assigned to each hour.
Hope this helps you out.
