1) To make the starter: combine the flours, water, and yeast, stirring till fairly smooth; the mixture will be thin. Cover and let rest at room temperature overnight, 12 to 15 hours.
2) Combine the starter with the flour, salt, and yeast, mixing and kneading to make a smooth, soft dough.
3) Knead in the toasted, cooled walnuts and diced dried apples. Note: To toast walnuts, bake them in a preheated 350°F oven for 8 to 10 minutes, till they're very lightly colored.
4) Place the dough in a lightly greased bowl or 8-cup measure (which makes it easy to track its rise), cover, and let rise for 60 to 90 minutes, till it's nearly doubled in bulk.
5) Gently deflate the dough, and divide it into 3 pieces.
6) Working with one piece at a time, shape the dough into a log about 12" long. Repeat with the remaining pieces of dough.
7) Place the logs in a lightly greased triple baguette pan; or on a lightly greased or parchment-lined baking sheet, leaving a couple of inches breathing (rising) room between them
8) Cover, and let the loaves rise for about 1 hour, till they're quite puffy. Towards the end of the rising time, preheat the oven to 425°F.
9) Make three long, diagonal slashes in each loaf. Spritz with water.
10) Bake the loaves for about 25 minutes, till they're a deep golden brown. Remove them from the oven, and cool on a rack.
Yield: three 14" loaves.