Contextual filters in Views - Filter by taxonomy
Retrieving the term ID by name has one considerable downside: If term names change, links may become invalid.

A safer option would be the use of aliases. For each of your terms, generate a URL alias per language that points to the internal view path (containing the term IDs). That way your view won't require custom logic to retrieve the term ID.

You could then expand on that approach and use e.g. the Redirect module to keep track of alias changes.

If you still want to stick to your approach, keep in mind that Drupal provides various functions to deal with paths and arguments. In your case, that one-liner can be simplified to:

$url_arr = arg();