Hmm. Well that changes things considerably.
In theory, the best time to train the technique would be during said lecture. The issue is, we don't know exactly when that lecture will happen, and the value of the technique is how quickly it can be obtained, and how broadly applicable it is.
Which leaves anyone who wants to train it in the unenviable pickle of deciding between training it now and potentially losing an action on it compared to people who train under an Elder for it, or waiting who knows how many turns for the lecture to be held and missing out on the extra die in their dicepool.
Depending on how things go. I'll likely either be holding the lecture next turn or 2 turns from now. It really depends on how the dice go for me.