A combination of sweet and sour is never that easy to handle in wine terms. The sweetness can make accompanying whites (I doubt if we're even thinking of reds here) taste thin and tart.
So a sweet wine I reckon and, even better, a sparkling one . . .
* Moscato has to be the number one candidate. Widely available, off-dry to sweet (like Asti), low in alcohol, it's just perfect with a sugar and lemon pancake. Authentic Moscato d'Asti is the tops if you can lay your hands on one.
* Prosecco would be my next choice. Most have a touch of sweetness, some (usually the cheaper ones) more than others. Check the back label.
* If you want something a bit more offbeat and have a good wine merchant nearby see if they have a Clairette de Die a delicious fragrant sparkling wine from the Rhône.
* or for a sweet wine I'd go for a late harvest or Beerenauslese riesling. Rieslings have a high level of acidity that can cope with the lemon juice - better than sweet wines like Sauternes or late harvest Sauvignons whose citrussy flavours will be wiped out by the lemon on the pancakes.
* A good cup of tea. Probably the most likely option if you're making them for the kids, if truth be told. And better with this type of pancake than coffee (think tea and lemon).
For wine pairings with other types of pancakes see here.