Because lemon sorbet brands vary so much in sweetness, I suggest making a batch of simple syrup ahead of time in case you need to increase the sweetness of the punch. See notes for simple syrup instructions.
Combine the lemonade concentrate, water, lemon juice and lemon-lime soda in a large punch bowl. Stir until well blended.
Add scoops of sorbet to the mixture; stir gently and let stand until the sorbet is almost completely melted into the punch mixture.
Add the pineapple sherbet in large heaps on top of the punch. Stir briefly. Let stand until the sherbet is partially melted and covers the entire surface of the punch.
Finally, pour in the 3 cups of ginger ale. The sherbet topping will foam and rise with this addition. Garnish with fresh berries and lemon slices, if desired.
To make simple syrup: Place 1 cup of sugar and 1 cup of water in a microwave-safe bowl. Heat in the microwave for 2 minutes; stir until sugar granules disappear. If the sugar granules do not dissolve after a few minutes of stirring, heat for an additional 1 minute at 100% power. This can also be made on the stove top over medium-high heat. Chill in the refrigerator before using. Add the simple syrup to the punch a little at a time, to taste.