In a medium pot cook the chorizo for 6 minutes. Remove excess fat if needed, leaving about 1 tablespoon. Add carrots,celery, onion and garlic and cook until the onion is soft. Add lentils and thyme and cook for 2 minutes, stirring constantly, taking care not to burn the garlic. Add water and tomatoes and simmer for 20 minutes. Add potatoes and simmer for 15 minutes. Add kale and simmer an additional 3 minutes. Season with salt and pepper to taste.