Form element is not rendered
I see two problems:

1) Your hook_theme() implementation is named incorrectly, meaning it will never be called. This:

_telisim_element_theme()


Should be this:

telisim_theme()


2) You haven't implemented theme_telisim_inline_form_element(), so there is no HTML for the form element to render.

You need to create this function, and output the relevant HTML for your form element inside the function.