Combine 3/4 cup semolina flour, all-purpose flour, pepper, and salt in the bowl of standing mixer. Whirl with the paddle attachment to combine.
In a 2-cup glass measure, combine and lightly beat lemon zest, 2 tablespoons lemon juice, olive oil, and eggs. With the mixer on low speed, slowly drizzle the egg mixture into the flour mixture. Stir to combine, adding additional semolina flour 1 tablespoon at a time until the dough comes together and is no longer sticky. Remove dough from the mixing bowl and knead by hand for about five minutes, adding additional flour only if needed to prevent sticking. Let dough rest for at least 20 minutes before forming pasta.
For the sauce, stir together creme fraiche, lemon zest, and lemon juice in a large bowl.
Roll pasta dough thinly and cut into strips by hand, or feed the dough through a pasta machine.
Boil pasta until tender – 1 to 4 minutes – in a large pot of salted water. Transfer drained pasta into the bowl with the creme fraiche mixture, stirring to coat pasta. Add arugula and the cheese and toss gently to combine. Season with salt and pepper. Top with Parmesan shavings, fresh arugula, and lemon slices.