For the ranchero sauce: In a large skillet over medium heat, heat the oil and saute half of the onions and half of the garlic until translucent. Add the poblano chiles and continue sauteing for 2 minutes. Add half of the tomatoes. Season with salt and pepper. Set aside.
In a blender, add the remaining onions, garlic and tomatoes. Then add the guajillo chile, jalapeno pepper, clove and ground cumin. Blend until smooth. Pour into the skillet. Add the chicken broth, marjoram and thyme. Continue cooking for about 10 minutes. Adjust seasoning if necessary. Keep warm.
For the lobster: In a skillet, melt the butter with the oil. Add the garlic and lobster meat, reserving some meat for garnish, and saute for 1 minute. Season with salt and pepper. Keep warm.
For the omelette: In a bowl, whisk the eggs and milk. Sprinkle with salt and pepper. Using a nonstick frying pan, heat the oil over medium heat and pour the egg mixture into the hot pan. Tilt the pan to spread the eggs evenly. Cook until the eggs have set. Add the cheese and lobster. Once the cheese has melted, fold one half of the omelette onto the other half. Transfer to a plate and serve with the ranchero sauce, more lobster on top and tortillas.