mapcar is not the best tool for the task, foreach in concert with apply would be a more appropriate fit.
(foreach args
'(
("A-GRID" 10 "CENTER2" "015" T 0 "Planning")
("A-GRID-OUT" 21 "CENTER2" "015" T 0 "Planning")
("A-MTRL-FBRC" 20 "Continuous" "018" T 0 "Windows")
)
(apply 'lyrmk args)
)