 His first passion was painting and he trained under Lorenzo Guerrero, Toribio Antillon, and Fabian de la Rosa.However, he pursued architecture and was sent to the United States as one of the first "pensionados" in architecture, after Carlos Barreto, who was sent to the Drexel Institute in 1908; Antonio Toledo, who went to Ohio State; and Tomás Mapúa, who went to Cornell.Arellano went to the Pennsylvania Academy of the Fine Arts in 1911 and subsequently transferred to Drexel to finish his bachelor's degree in Architecture.