Published in 1902, this piece is by the young Tournemire and is quite different from the Orgue Mystique or 7 Chorals-poèmes.
It's, IMHO, a good deal above standard pastoral stuff of this period (Bonnet, Claussmann and so many other ones) and has some Debussy's flavour.
St-Omer was chosen because of its very fine bourdon 8', which is much at work in this piece.
BTW : from now, I'll try to use my organ time mainly to re-learn pieces already uploaded instead of learning new things ; if I manage to stick to this objective, there shouldn't be many uploads during the next months : one cannot be everywhere :-)