You can also add your lisp program to the your Acad.lsp, which is loaded automatically (if acad is set to do that).
You can also add a startup command to the acad.lsp like this:
(DEFUN S::Startup ()
(load"dothis.lsp")
)
Place at the very beginning of the acad.lsp file.
In options, you have to specify that acad.lsp is loaded with each drawing.