Prepare the pasta according to the package directions, cooking until al dente. Reserve ¼ cup of the pasta cooking water. Scoop the hot pasta into the pot, along with the reserved pasta water, the arugula, and toss. If necessary, gently heat until the arugula wilts and the pasta is warmed through. Add the thyme, tomatoes, lemons, and toss again. Top with the mozzarella, pine nuts, and basil. Gently toss, season to taste and serve.