Reading that classic of children's literature, Tiptoes the Mischievous Kitten (a Ladybird book from 1949), I started wondering about the phrase "of course."
Here's an example of what I think of as the typical use of "of course": after getting covered in starch, Tiptoes runs out into the sun where "of course her fur dried in little stiff points... ." If you get mixed up in starch, then it's gonna dry your fur in stiff points -- here, of course "acknowledges the validity of the associated phrase."
But here's another example of "of course" that I think of as less typical and this is the one I'm asking about. Tiptoes's owner carefully closes a door, but, the latch being loose, it swings open again. At this point in the narrative, my two young children know that the very worst thing that could happen is that the mischievous kitten comes along, but "Just then, of course, Tiptoes came silently up the stairs" (and then all hell breaks loose).
This use of "of course" does not acknowledge the validity of the associated phrase: it does not follow from the door swinging open that Tiptoes should happen up the stairs. She could just as well be sleeping in the rocking chair or hunting mice.
It seems instead to mean "as luck would have it," or acts perhaps an idiomatic affirmation of Murphy's law.
I can remember my English grandmother using the phrase "of course" in a similar way, usually in humorous or ironic stories. She'd use an "of course" to introduce that the worst/silliest/funniest possible turn of events was about to happen.
Is this usage mainly mid-20th-century English? Is it any accident that an English book of 1949 reminds me of something my English grandmother (born in 1916) might have said? I don't think I've heard it used amongst my Canadian contemporaries. Do we still hear it today, or has it been replaced by other idioms or even tones of voice? Do we hear it in North America, in Australia, NZ, South Africa, India? Is its use limited to the British Isles, or even to certain regions of the UK?