In a medium bowl, whisk together the sour cream, chives, honey, orange zest and juice and salt and pepper to taste.
In a large bowl, add the arugula, walnuts, raisins, apple and celery. Toss to mix, then add a spoonful of the dressing at a time, tossing between additions, until the salad is lightly dressed. Serve topped with shaved Pecorino-Romano.