In a medium saucepan, bring the water and sugar to a boil. Stir until sugar is dissolved. Reduce heat to low and simmer, without stirring, for 5 minutes. This will create a slightly thickened syrup.

Pour the syrup into a medium bowl and transfer to the freezer to let chill for 15 minutes.

Using a blender or food processer, puree 1 pound of the raspberries with the syrup until smooth. Scrape the puree through a fine sieve or a colander lined with cheesecloth. Discard the seeds.

Stir the lemon juice into the raspberry puree and freeze in an ice cream maker until almost set, but still a bit slushy. This should take about 25 minutes. Add remaining whole raspberries and continue freezing in the ice cream maker for an additional 5 minutes.

Transfer the sorbet to a freezer safe container and freeze until completely set. A solid set can take a couple hours or more. When the sorbet is frozen solidly, it helps to let it sit at room temperature for 10 minutes before scooping.