Durango Stew

8 ancho chiles, seeds and stems removed
1 cup water
2 to 3 pounds pork, cut into 1/2-inch cubes
3 tablespoons vegetable oil
1 large onion, chopped
2 cloves garlic, chopped
2 teaspoons flour
2 large tomatoes, peeled and chopped
2 to 3 cups beef stock
1/4 teaspoon dried Mexican oregano
2 tablespoons lemon juice
Salt and pepper, to taste

Cover the chiles with water and simmer for 15 minutes until they are soft. Pur