I would expect English people to use the
German pronunciation, or as close to it as they can get: lee-zuh-lo-tuh.
I wouldn't expect to find it used in English-speaking societies unless there was a very good reason: a grandmother named
Elizabeth Charlotte, or - like you - an interest in history.
Where I live, Afrikaans-speaking people typically learn
German at school as a third language, and use both
Elizabeth (various spellings) and
Charlotte to name their daughters, but I've never seen a
Liselotte locally. And other blended names are widely used, so that's not the issue. Perhaps it's just inconveniently long.