"Mi faris prelegon en la klubo pri Esperanto."
Translation:I gave a talk in the club about Esperanto.
I noticed that, too. I think the sentence would have been more clear if it said, "Mi faris prelegon pri Esperanto en la klubo."
A 'club about Esperanto' is usually called "klubo de Esperanto" (or "Esperantoklubo").
It is better to put "pri Esperanto" directly after (or before) "faris prelegon" (or "prelegis").
Does "hold a lecture" also work in English, or is this a Germanism (einen Vortrag halten)?
Google finds examples, but they may be from non-native speakers.
I am a native speaker in a native speaking country and in our state university you will often hear "hold a lecture" or "held a lecture" used.
The "standard language" is sometimes the language of the person who first edited dictionary in a given language. Martin Luther translated the Bible into German and his language become "standard German", although other dialects remain in other regions, which are widely used there.