Combine the shallot, vinegar, 1 teaspoon thyme, 1 teaspoon salt and 1/4 teaspoon pepper in a medium bowl. Gradually whisk in the olive oil, starting with a few drops and adding the rest in a steady stream.
Put the pork chops in a shallow dish and season all over with salt. Add 3 tablespoons of the dressing and the remaining 1 teaspoon thyme. Rub all over the pork and let marinate 5 minutes.
Heat a grill pan over medium-high heat. Grill the pork until just cooked through, 4 to 5 minutes per side.
Add the grapes and arugula to the remaining dressing and toss to coat. Transfer the pork chops to a serving platter or individual plates; top with the salad and sprinkle with the gorgonzola.