The Office from from Ash Wednesday
Lent officially starts this Wednesday. In the Office though, the rubrics don't really change much until after the First Sunday of Lent.
The period from Ash Wednesday to the coming Saturday was something of a 'later' add-on to Lent to make up the correct number of days (given that Sundays are not counted for fasting and other purposes, although in reality we still don't quite make it to forty days, due to the several first class feasts that intervene).
The liturgy does intensify a little however, with canticle antiphons for both Lauds and Vespers, for each day. At Matins, the readings are Patristic, on the Gospel of the day. The rest of the Office at Lauds to Vespers, though, remains that of 'throughout the year' up until the First Sunday of Lent.
The Benedictine (1962) Office this week in summary
Sunday March 2 – Quinquagesima Sunday, Class II
Monday March 3 – Class IV
Tuesday March 4 – Class IV (Shrove Tuesday) [EF: St Casimir]
Wednesday March 5 – Ash Wednesday, Class I
Thursday March 6 – Thursday after Ash Wednesday, Class III; SS Perpetua and Felicitas, memorial
Friday March 7 - Friday after Ash Wednesday, Class III; St Thomas Aquinas, memorial
Saturday March 8 – Saturday after Ash Wednesday, Class III [EF: St John of God]