Yes you can but you have to change the post a bit so it displays well on lemmy.
The first line is taken as the title so currently your post is just named „@asklemmy“.
Probably, I don’t know much about Mastodon so I can’t say what will work on that side. But as long as you make sure that it isn’t the first line by itself or not in the first altogether it will probably be fine from the lemmy perspective.