I'm reading Benedict XVI's "Jesus of Nazareth: The Infancy Narratives" and he indicates how Gabriel appeared to Zachariah in the evening. Also Gabriel appears to Daniel (Dn 9, 21) at the same hour:
As I was yet speaking in prayer, behold the man, Gabriel, whom I had seen in the vision at the beginning, flying swiftly, touched me at the time of the evening sacrifice.
Now, I can't confirm that Gabriel appeared to Zachariah in the evening sacrifice, because there apparently were two "incense sacrifices in a day", one in the morning and another in the evening. But it would make sense if it was in the evening.
Things get more interesting. We only know of Gabriel because of the book of Daniel and because of these two apparitions in Luke. Two of them apparently happened in the evening. What about Mary? Benedict XVI doesn't say as far as I've read but he points out to Psalm 141, 2:
Let my prayer be directed as incense in thy sight; the lifting up of my hands, as evening sacrifice.
The question therefore is: Do we know of any biblical text that says if Mary was praying before Gabriel's apparition? What about any interpreters, commentaries or traditions that made a case for it?
Thank you all and God bless you.