I have walked from Lourdes to Santiago twice. Lourdes is a faith event if that is what you want to experience, nevertheless the town is exciting with a nice market. I prefer to walk from there SJP due to a serene and quite Camino with places to stay.
I love Lourdes - we walked from Lourdes to Somport Pass and then along the Camino Aragones (a stunning route). Howsever, not everyone enjoys Lourdes - you need to look beyond the commercialisation of it to appreciate it. Make sure that you are not there over the weekend as it gets quite hectic. It is also worthwhile spending the night there so you can participate in the candlelit procession.
I was in Lourdes many years ago. Pre Camino days. The procession and the church grounds is an experience I found very worthwhile and in some ways profound. I am spiritual but do not believe in organized religion etc. But I found the night there to be a moving experience. The town itself was awful. Full of hundreds of shops peddling the same religious and touristic artifacts. My humble opinion.
Definitely worth while. For my last camino, took a flight from Madrid to Toulouse and a train to Lourdes and attended the procession. Don't know how to get from Nogaro to Lourdes. You can research on the web or while you are walking inquire at the local tourist office. I don't know if you plan to go back to Nogaro to continue to Lourdes, but you can walk from Lourdes to SJP via Piemonte route. Info is available via this forum:
Went to Lourdes prior to starting my 2016 Camino. Participating in the evening procession helps one put the commercialism in place. It is amazing that people from all over the world travel there. I reccomend going.
Thank you all for your comments. I have decided to include the daytrip tot lourdes into our program but plan to walk the camino day by day without putting too much thought into it this time around. So will see if it takes us there. Two and a half months and counting....