The part of Claire had particular resonance for Vanessa Redgrave as she too had traveled to Italy as a younger girl and stayed for a period of time, much like her character.
There are a total of 13 Lorenzo Bartolinis in the film, including the deceased one, the son and grandson of Claire's lover and the ones that appeared one after another.
When Sophie first walks into the area with Juliet's wall, you can see a man taking a picture walking with his family over her left shoulder. The camera cuts to show the wall and then back to Sophie, where the man once again appears walking behind, taking a picture.
When driving around Italy, looking for Lorenzo, they are alternately shown driving on the left and right sides of the road. In Italy they drive on the right side of the road. This may be due to some frames being flipped (left-to-right).