Yes, it works.
It's sort of a short-cut way of "twice frying" your french fries.
I don't do it with french fries, but I often fry things by dumping cold oil on hot foods. I start frying (usually battered shrimp or egg rolls) in hot oil to start the cooking process and the vaporizing, then I dump in cold oil until the hot oil stop sizzling. Then remove when the oil begins to sizzle again.
The theory is that it still cooks the food without overbrowning or overcooking the food -- an oil poach, or an oil sous-vide, if you will.
It's the same principle with cold oil frying.
The end result is food that’s cooked evenly, without being greasy, but still nice and crispy because once the oil reaches a sizzling temp, it will evaporate all the moisture from the food.
When I do this with battered and butterflied shrimp, you get this fluffly and crunchy shell that really showcases the tenderness of the shrimp.