They called him this because "Lo" was kind of a nickname within a nickname. The "Lo" part, comes from "Lothario'', in which he was also commonly called. Both the nicknames are Latin. (Don't ask me what "Lothario" means.) He was Latin, and from what I understand, this nickname fit General Armistead perfectly.
He was mortally wounded in the Battle of Gettysburg, and died 2 days later.
No. General Lewis Armistead and General Hancock both knew each other from fighting together in the union army back before the battle of Gettysburg. General Lewis Armistead fought with the Confederate Army, Under General James Longstreet. Lo Armistead was also involved in the valiant charge against the union center, a move known as "Pickett's Charge." General Hancock was a newly appointed corps commander at the battle of Gettysburg. When Hancock's friend, Maj. General John Reynolds was killed, Hancock was appointed to command Reynolds remaining forces. On July 3rd, 1863, Pickett's Charge commenced. When Armistead reached the center of the union army, he was struck by a union bullet and died two days later. Armistead never got to see his old friend because just beforehand, General Hancock was struck by a Confederate bullet and carried away. Hancock survived his wounds, but never saw his old war friend. Armistead, on his death, left Almira Hancock (Hancock's Wife) a copy of his personal bible. Two friend, fighting against each other, but never to see one another again. Sad.
Susanna Lo's birth name is Susanna Lo.
Candy Lo's birth name is Lo Hau-Yam.
Guan Lo's birth name is Lo Kuo-Tse.
Hollie Lo's birth name is Hollie Beatrice Lo.
Kenny Lo's birth name is Lo Kin Ming.
Ken Lo's birth name is Kenneth Lo Wai-Kwong.
Edmund K Lo's birth name is Edmund Kayyuen Lo.
Saverio Lo Medico's birth name is Saverio Francesco Lo Mredico.
Paul Lo Duca's birth name is Paul Anthony Lo Duca Jr..