@Orestes and Geoff (and OP)
Of course in my previous post I was being a bit "dogmatic" about the "normal" use of the Lesson activity.
However, I tend to disagree with Orestes that "question logic can be (ant ought to be) separated from lesson flow logic". In my pedagogy, a Lesson (and a Quiz) need to be constructed with relevant questions which follow one upon another, and certainly not questions chosen "at random". That's why I have no use for the "random questions" feature of the Quiz activity, for example.
Of course I'll have to admit that there are other views in this matter.
@Orestes: The feature you are alluding to has cropped up from time to time over the years in these forums but nothing has come out of it. For quite a few years, unfortunately, the Lesson module no longer has an active maintainer, unlike the Quiz module, where Tim Hunt is very active. The Lesson module is almost an "orphan" in the Moodle development strategy - at the moment.
Joseph