How to add code to top of author page via plugin?

Hey There,

I’m currently coding a plugin that adds an author box to the top of the author archives page and a link below any other archives pages. I have been attaching my function to loop_start however this seems to also add the code inside my recent posts widget on the sidebar.

function custom_author_box_plugin() {
	global $post;

	$curauth = (get_query_var('author_name')) ? get_user_by('slug', get_query_var('author_name')) : get_userdata(get_query_var('author'));

	if (is_author()) {
		?>
		<div>The Author Box code here</div>
		<?php
	}
	else if (is_archive() && (!is_author())) {
		?>
		<div>Code for standard archives here.</div>
		<?php
        }
}
add_action('loop_start' , 'custom_author_box_plugin');

Can anyone guide me in the right direction for only showing the code in the relevant place rather than what I presume is another loop on the page inside a widget?