Beauvais airport to Lourdes

Hi

I was planning on heading over to Lourdes in July but Ryan airs flights are limited. Flights to Paris are far more frequent so I was thinking of flying to paris and then getting a train to lourdes. However looking at the map it appears as though Beauvais airport is not exactly in Paris and the train station(Montparnasse)is a fair bit away from the airport. I;ve heard that theres a shuttle bus ryan air provide the goes from Beauvais to paris, but does anyone know where this bus leaves you in relation to the train station?

Thanks