Complex sentence: Joyce's Leopold Bloom is in the advertisement business working as a canvasser, but at one time he worked for Hely's stationery and printing company (possibly out of Dame Lane), as a commercial traveller.
Split into simpler sentences: Joyce's Leopold Bloom is in the advertisement business, working as a canvasser. At one time he worked for Hely's stationery and printing company (possibly out of Dame Lane), as a commercial traveller.