Before a Low Mass, the priest ascends the Altar to place the Chalice, check the altar Missal, and do other “preparing” tasks. The organist must be prepared to play here, and—depending upon the priest—this can be of surprising length! For certain priests, I can easily play all six verses of a hymn while he’s doing these tasks. In the Ordinary Form, I believe too many have abandoned the preparation time before Mass (vesting, praying, keeping silence, and so on). I remember waiting for a priest to arrive in Corpus Christi, so I could ask him about the music. He never did arrive, because he had gotten into his vehicle wearing his chasuble, parked, hopped out of his truck (fully vested), and literally “processed” in as he entered the Church…true story.