Heat the oil in a large pot over medium heat.Once the oil is shimmering, add the onion, celery, carrot, season with salt and pepper, and cook, stirring often, until the onion has softened, 3-5 minutes. Add the garlic, basil, thyme and oregano. Cook until fragrant while stirring constantly, about 30 seconds. Add the tomatoes and stir thoroughly to combine.Add the lentils, broth, and bay leaves. Season with red pepper flakes, salt and pepper. Raise the heat to high and bring the mixture to a boil, then cover the pot partially and reduce heat to medium-low and let simmer for 20 minutes or until lentils are almost tender.While the soup cooks, peel and spiralize the turnip using Blade C and trim the noodles. Set the noodles aside. After 20 minutes, remove the bay leaves, add in the turnip noodles, stir to combine and let cook for 5-7 minutes more or until lentils are fully tender and turnip noodles soften.Stir in the lemon juice and serve.