What tense it this?

From “The Lion King”:

“From the day we arrive on the planet
And, blinking, step into the sun . . .”

What tense are “arrive” and “step”?

The easy answer is “present tense,” but it seems like a special case, because the verbs describe something that collectively happened in the past, and continued to the present . . . and into the future.

So is there a subset of present tense that would apply to this situation?

I think that, grammatically, “arrive” and “stop” are just in simple present tense. Despite the name, present tense is often used to indicate things that happen in the future, or past, or are a sort of ongoing and continuous state of things – as in “I leave for Leningrad next week,” or “bears don’t eat purple grapefruit.”

Verbs in present tense can be combined with auxiliaries forming various moods and aspects (which sometimes have their own temporal meaning), but that isn’t the case here. In the song, both verbs are present indicative, same as the verb in “Bob defenestrates the lungfish.”

The historical present.

Wigwam

It’s actually quite hard to think of examples of the so-called present tense being used to describe discrete events that are occuring at that moment. If you were to describe your current activity, you wouldn’t say “I browse the web”, you’d say “I’m browsing the web” (the auxiliary verb is in the present). I suppose if you’re watching sport on TV the commentator might say “he picks up the ball, he runs into space” or whatever. But they also use that form when describing footage of past action.

Indeed, it’s most often analogous to the AAVE “habitual be” in that it most often indicates that the activity takes place on a regular basis.

The real problem (as many others in the description of English grammar comes from the attempt to shoehorn the grammar into that of Latin. English has two tenses, which should probably be called the timeless and the perfect, but are actually called the present and (simple) past. All actual temporal relations are expressed by the context. There is, for example, no future tense in English, just various ways of expressing the future. "I am going to my office tomorrow’, “I will go to my office tomorrow”, “I am getting ready to go to my office tomorrow” all express futurity and it is silly to single one out and call it the future. “I go to my office every day” expresses no time at all.

The given examples are simply the timeless form.

ISTR a guideline, issued by lab instructors in science courses, that encouraged students to write up their procedures and observations in present tense. This practice, they argued, would avoid opening up the lab report to criticism that the lapse in time between observation and writing (implied by past tense) calls into question the accuracy of the qualitative descriptions.

Well put. To avoid confusion, though, better to say “there are only (at most) five inflectional verb forms” – (no ending), -s, -ing, (simple past, typically -ed), (perfect, also typically -ed), and that two of these can be used by themselves to indicate a tense, while the others indicate other tenses when used in combination with auxiliary verbs. (The others can also be used by themselves to indicate things which aren’t really tenses, but rather verbs acting as other parts if speech – gerunds, etc.).