老 + surname is the standard friendly-but-respectful form of address among adult Chinese colleagues, especially for someone roughly the speaker's age or older. Counterparts:
小 + surname for someone younger (
小范 'Young Fan'),
老 + surname for someone the same age or older.
范 (Fàn) is a moderately common surname - historical bearers include Northern Song reformer Fan Zhongyan (
范仲淹) and contemporary actress Fan Bingbing (
范冰冰).
