Perhaps online searches will bring people to this post. If you are searching for Holy Mass in the Extraordinary Form while in Lourdes (during the pilgrimage season, roughly from April to October), it is offered in the upper Basilica every Sunday at 9:00 a.m.
The FSSP have a nice maison in Lourdes, named Our Lady of Victories (a great church to visit in Paris, by the way). They staff a parish community in nearby Tarbes (the seat of the diocese that Lourdes is located in) and during the pilgrimage season their wonderful priests help each evening with the outdoor procession at the grotto.
Watch for them and say hello. Their work here is crucial. Lourdes is the de facto center of Catholic life in France where the bishops meet and many events are held.