In large saucepan, combine chopped broccoli, broth, onion, lemon juice, garlic, pepper and 1 cup water; bring to a boil. Reduce heat to medium; cook, covered, 12-15 minutes, until broccoli is tender, adding more water, 1 tablespoon at a time, if liquid begins to evaporate.
Transfer broccoli mixture to food processor; puree until smooth.
Return broccoli mixture to saucepan; stir in milk. Cook over low heat, stirring frequently, until hot (do not boil).
Just before serving, ladle soup evenly into 4 soup bowls; garnish each portion with broccoli florets if desired.