In a large bowl, dissolve yeast and sugar in warm water. Stir in lard, salt and two cups of the flour. Stir in the remaining flour, 1/2 cup at a time, beating well after each addition. When the dough has pulled together, turn it out onto a lightly floured surface and knead until smooth and elastic, about 8 minutes.
Lightly oil a large bowl, place the dough in the bowl and turn to coat with oil. Cover with a damp cloth and let rise in a warm place until doubled in volume, about 1 hour.
Deflate the dough and turn it out onto a lightly floured surface. Divide the dough into two equal pieces and form into loaves. Place the loaves into two lightly greased 9x5 inch loaf pans. Cover the loaves with a damp cloth and let rise until doubled in volume, about 40 minutes.
Preheat oven to 425 degrees F (220 degrees C).
Bake at 375 degrees F (190 degrees C) for about 30 minutes or until the top is golden brown and the bottom of the loaf sounds hollow when tapped.