Make the syrup: combine the cranberry juice, honey and 2 rosemary sprigs in a small saucepan. Simmer over medium heat for 5 minutes, then remove from the heat and steep for 10 minutes. Strain out the rosemary and cool the syrup for about 15 minutes; it makes about 2 cups.
Stir the cooled syrup and lime juice together in a large pitcher.
Add the sparkling water slowly and stir once, gently, just to combine so the bubbles stay.
Fill 6 glasses with ice, pour the mocktail over, and garnish each glass with a rosemary sprig, a few cranberries and an orange slice. Serve right away.