I don’t think any snow in Chicago is ever “lake effect” snow, for the simple reason that it’s rare for winds to blow east across Lake Michigan. Lake effect snow – take it from someone who has experienced plenty of it – happens when cold air passes over an unfrozen lake, picking up water vapor from the lake, and then dumping the moisture as snow when the air currents hit cold land again, usually some sort of hills (also not a big feature of Chicago). Early in the season each winter you get bands of lake effect snow coming off the Great Lakes going northwest to southeast. So there’s lots of lake effect snow in Michigan, and in Ohio, and central and western Pennsylvania and New York. Chicago, not so much.