Use a blender or food processor to puree the strawberries. Strain them through a fine mesh sieve, if desired, to remove seeds.
In a small saucepan, over medium heat, stir together sugar and 2 cups water.
Bring to a boil, and stir until sugar is dissolved. Remove from heat and allow to cool to room temperature.
Strain the lemon juice through a fine-mesh sieve into a 2-quart pitcher. Add simple syrup and pureed strawberries and stir to combine. Refrigerate until cold.
When ready to serve, add 2 ½ cups of cold water and stir. Taste, and add more water if it's too sweet.
