Using the invitatory at the office of Vigils I read the Office of Readings every day. On Sundays and solemnities, I read it as a vigil office, before Compline/night prayer.

I know broadly how to do it -- after the second responsory, you read the seasonal canticles, then the gospel of the Sunday/solemnity, followed by the closing prayer.

I'm interested, however, in one particular detail.

This is the invitatory. This is supposed to be said before the first office of the day, which for me is almost always the Office of Readings. I'm not sure what to do, however, if I'm reading the Office of Readings as the Office of Vigils the previous evening.

Should the invitatory be said at Vigils, or is it said at Lauds on those days?
The answer is that you should not read the invitatory at Vigils, as it is meant to begin the day's prayer.


  
  The invitatory is placed at the beginning of the whole sequence of the day's prayer, that is, it precedes either morning prayer or the office of readings, whichever of these liturgical rites begins the day.
  -General Instruction of the Liturgy of the Hours