The annotation can be found here on the left page, to the right of the rightmost column, near the top. This column is a couple words into 1 Kings 18:27 :
I see that I remembered it wrong: it's just two lameds, no waw. The lameds in these scribal annotations (specifically these are masora qetana) are written with a dot behind them. I must have misread the dot between the two as a holam, signifying the vowel /o/, which is what yielded the word "LOL". So this joke is even more of a stretch than I thought.
If you follow that link to masora qetana, you'll see that these lameds are short for the Aramaic phrase ליתא דכוותיה leita dikhvateih and mark single-occurrence words (hapax legomena). You can identify the marked word by a little almost-closed circle above it in the line.
In this line, they pick out the words שיג and וכי־דרך. Both וכ "that, since, as" and דרך "road" appear many times in the Bible, but the scribes also identified unique compound forms.
But the first word, שיג, is interesting since its meaning seems to be disputed; see here and here. The link to dross or waste seems to underlie translations that have Ba'al "doing his business". At this time, though, the exact insults Elijah uses to taunt the prophets are not clear from this passage.
Some other annotations are also explained on that page, which is worth a read if you're curious!