To make the syrup, combine the cold water with the sugar in a medium-size saucepan. Boil the mixture for 5 minutes, then lower the heat and simmer, uncovered, for about 15-30 minutes. The syrup is ready when it is light yellow, and when a small spoonful dropped onto a wooden surface is tacky when cooled. Once ready, stir in the lemon juice into the syrup and set it aside to cool.