Prepare a bowl of water and two halved lemons. Squeeze 3 of the halves into the water and reserve one half. As you work, rub the reserved lemon half over the cut surface and immediately put the trimmed artichokes in the lemon water to slow the oxidation.
Pull off the outermost leaves of the artichokes until you get down to the lighter yellow leaves. Then, using a serrated knife, cut off the top third or so of the artichokes and trim the very bottom of the stem. Peel the stem, using either a paring knife or a y-peeler to remove all the tough green exterior. Cut the artichokes in half lengthwise. With a spoon or melon baller, scoop out and discard the hairy choke and thorny inner leaves.
Slice cleaned artichokes and drop them in your bowl of acidulated water. Drain and pat dry. Heat 4 tbsp extra virgin olive oil and garlic in a large skillet over medium-high heat. When fragrant add the artichokes and sauté until crispy, about 4 minutes. Pour in broth and orange juice, and cook 3-5 more minutes. Season with salt and pepper to taste, add shrimps, thyme and orange zest and sauté for another 2 minutes until cooked trough.
In the meantime cook Tortelloni according to package instructions and drain, reserving a ladleful of the pasta cooking water. Add the pasta to the pan and stir gently, adding some of the pasta water if you need to loosen the sauce. Divide among 2 plates and serve.