Place the water and stock in large saucepan with chicken, carrot, celery and onion; bring to boil. Reduce heat; simmer, covered, 1 and half hours. Remove chicken from pan; simmer broth, covered, 30 minutes.
Strain broth through muslin-lined sieve or colander into large heatproof bowl; discard solids.
Melt butter in large saucepan, add flour; cook, stirring until mixture thickens and bubbles. Gradually stir in broth and juice; stir over heat until mixture boils and thickens slightly. Add cream, reduce heat; simmer, uncovered, about 25 minutes, stirring occasionally.
Meanwhile, remove and discard skin and bones form chicken; shred meat coarsely. Add chicken to soup; stir over medium heat until hot.
Sprinkle soup with parsley; serve with crusty bread, if you like.