I can't find anything more definite, but it sure does look to me as if Mrs. La Tournelle knew and awful lot about theatre in general! Perhaps she was the offspring of actors- or theatre managers, or something. Do you think she did "real, hardened acting" of the kind that Edmund Bertram enjoyed?

Presumably, then, she was also good at holding an audience's attention, and perhaps quoting the odd bit of Shakespeare or Dryden to enliven classes. I must admit I think I would have found her a lot of fun!