This is actually a machokes rishonim, and machlokes haposkim [a dispute among the commentators]. The root of the question is: Do we say that when I make a bracha, it goes on all the food I am going to eat? Or does it really only go on the food I am holding and intending to eat first, and the rest of the food only is "dragged along" with the first food?
This is discussed in Shulchan Aruch (O.C. 206:6) and the commentaries.
The Mishna Berurah and Beur Halacha explain that there are three opinions in the rishonim, all of which are brought by some poskim:
Tosfos and Rosh assume that the bracha only goes the item being held, while all the rest of the almonds are only "dragged along" and included with the first one. So if the first one gets lost, one must make a new bracha before eating from the other ones. This is true even though they were all in front of the person while he made the bracha! This is how the Mechaber (R' Yosef Karo) rules.
Kol Bo in the name of Rabbeinu Tam, Maharil, Abudarham and other make a distinction on what sort of intention you have. If you had explicit intention to cover the other fruit, then we say your bracha was intented on those ones as well. So you could eat the rest of the almonds even though the first one was lost. This opinion holds that if the first one was not lost, and you in fact ate the first almond, then you can eat the rest of the almonds even if you only had "stam daas" (i.e. you didn't specifically think about eating the rest, but if was a possibility). In this case, these opinions would agree that the rest of the fruit would be "dragged along" with the first almond. This is accepted as halacha by the Rama (R' Moshe Isserles). These opinions only differ with the first opinion regarding whether it's possible to expressively include multiple fruits with your intention, or whether we always only "drag along" the other fruits.
The Raavad and R' Gershon ben Shlomo add an additional layer- even if a person has "stam daas", whatever is in front of him at the time of the bracha is included in his intention. The "stam daas" only applies to food which wasn't in front of him when he made the bracha, but he might have gotten (i.e. he has more almonds elsewhere which he could eat.) Those foods are "dragged along". But whatever he has in front on himself will always be included, unless he explicitely excludes them ("I am planning on not eating these almonds") The Beur Halacha says that the Mabit held this way.
The conclusion of the Beur Halacha is that safek brachos lehakel, since there's a doubt about what the halacha is, we would not go back and make a new bracha. So if you have almonds in front of you, and the one you held while making the bracha got lost, you would just take a new almond from the pile and eat it with no new bracha.