Preheat oven to 375 degrees.
On a lightly floured surface, roll out each sheet of dough, still folded,into a rectangle about 10 x 14 inches.
Cut each rectangle into quarters to form 8 small rectangles.
Combine cherries, flour, sugar and lemon juice.
Toss to coat.
Mound cherry mixture on one side of the rectangle, leaving a 1/2 inch border.
Lightly brush border with water and fold other side of pastry over cherry mixture and press edges firmly to seal.
Using a fork, crimp the edges.
Transfer turnovers to a baking sheet.
Cut 3 slits in the top of each turnover.
Brush tops with an egg wash and sprinkle with sugar.
Bake for 30-40 minutes until turnovers are golden and puffed.