[Tex/LaTex] \marginpar with options

Question

I was trying to understand what Leslie Lamport said in his book about \marginpar options. He says that

… \marginpar[$\Rightarrow$]{$\Leftarrow$} makes an arrow that points towards the text, whichever margin the note appears in. (Page 59)

I am not sure what he meant by "text". I was hoping that it is the non-marginal text and the arrow would appear in the margin before the margin text. The following is an experiment to test this hypothesis.

\documentclass[11pt]{article}
\usepackage[margin=2in]{geometry}

\begin{document}
This is normal text.%
\marginpar{\em This is a marginal note.}

\vspace{100pt}
This is normal text.%
\marginpar[$\Rightarrow$]{$\Leftarrow$}{\em This is a marginal note.}
\end{document}  

As you can see the hypothesis is false.

Is it possible to make the arrow followed by the marginal note appear in the margin?

EDIT: Apparently, I did not make myself clear in my first attempt. As you can see in the second example (\marginpar with options) the marginal text (in italic) which is supposed to be in the margin is not in the margin anymore. What I was hoping to see is the following.

If this is not what the options for \Marginpar are there for, then I do not see why I need these options.

Answer 1

lamport didn't say anything about additional text when using the arrows. what he did say is that if you use the option, that's what goes on the odd page instead of what's in the required argument. each argument must be complete with what you want in that margin.