Arnold was ranked as high as ninth during his junior career, which included winning the South American Championships in the 14s and 16s categories, in 1985 and 1987, as well as the Banana Bowl in 1989.

[2] In 1991, on his ATP Tour debut, Arnold upset world number 51 Amos Mansdorf at Long Island's Norstar Bank Hamlet Challenge Cup.

[2] Arnold was selected to play the fifth and deciding rubber of a Davis Cup tie for Argentina in April 1995, against Venezuelan Maurice Ruah.

[3] In the 1995 French Open he teamed up with Orsanic but the pair were unable to progress past Byron Black and Jonathan Stark in the first round.

[2] He changed his partner for the 1995 Wimbledon Championships, choosing to play with Jorge Lozano, but they would be defeated in the opening round by Trevor Kronemann and David Macpherson.