Madelgarde de Lommois, concubine of Charlemagne - de Lommois - sources?

I don't have it in my notes, but a quick search shows French Wikipedia:

http://fr.wikipedia.org/wiki/Madelgarde

No sources cited.

MedLands infers her name as [Madelgard], but gives no details.

http://fmg.ac/Projects/MedLands/CAROLINGIANS.htm

Thanks Justin Swanström.

The Frennch wikipedia link you cite says this:
Madelgarde (? -), daughter of Madelbert Lommois, Count of Hainaut and Duke of Dentelin . In 802 , Charlemagne took the married or concubine.
From this union was born a daughter or Rothilde Ruothilde or Clothilde (784 - † 24 March 852), abbess of the Abbey of Notre-Dame and Saint-Pierre de Faremoutiers

I'm thinking that might be sufficient to leave it in?

Yes, I think we should leave it. Someone, someday will find a primary source and we can revisit it then.

:-)