The Atlantic City resident, who has spent several years in jail on fraud charges, sat quietly through the selection process, which is expected to last several days.
He has been held on $2 million bail since his arrest on May 28, 2010.
The prosecution's case was recently bolstered when Arno's girlfriend and alleged partner in crime pleaded guilty and agreed to testify against him.
At a hearing on Feb. 14, Jessica Kisby, 26, provided a chilling account of the murder of Martin Caballero, 47, a Hudson County grocer who had come to the Taj Mahal on May 21, 2010, to celebrate the birthday of his daughter with family members.
Kisby testified that she and Arno targeted Caballero because he was driving "a nice car."
"We figured he had money," she said.
Caballero was forced into the trunk of his 2009 Lincoln MKS and driven from the garage. Kisby said she and Arno used his credit card to make an ATM withdrawal of about $300.
Later, she said, Arno stabbed Caballero to death. They dumped the body on a dirt road in Hamilton Township, Atlantic County, she said, and drove the Lincoln to Gloucester Township, where they set it on fire.
Kisby said she and Arno never discussed killing Caballero. "It just happened," she said.
Kisby, an Egg Harbor Township resident and single mother of a 7-year-old daughter, will be sentenced to 30 years in prison with no parole under the terms of her plea bargain. She will receive credit for time she has spent in prison since May 2010.
Donio is expected to continue questioning potential jurors on Thursday. The goal is to create a pool of about 50 "qualified" jurors. Twelve jurors and four alternates will be chosen to hear testimony.
The trial is expected to last about five weeks.
Contact staff writer George Anastasia at 856-779-3846 or ganastasia@phillynews.com.