Thanks, Steve - It can't be strumming, because plucking is also meant by schlagen. It stands for every technique with the lute. So striking sounds not too bad.
My daughter, the soprano, is afraid that it will be a musical Christmas. She heard me training the basso of a Bach aria on the flauto alto, and is also afraid that I will insist on our doing it together to please her mother. "How right you are, my dear" I told her.

Wilfried